[ RadSafe ] DNA Repair

Brennan, Mike (DOH) Mike.Brennan at DOH.WA.GOV
Wed Oct 21 11:58:11 CDT 2015

Hi, Andy.

I think a very interesting line of research would be if epigenetic mechanisms "switch off" genes that have errors in them at a higher rate than those that do not (what constitutes "error" is, of course, an interesting question, as the assumption is that everything in the genome was an error at some point).  This would allow for a larger accumulation of change in the genetic material without expression until something removed the "switch off" mechanism, and allowing for "punctuated equilibrium" without having to have the rate of error change in response to the environment. 

-----Original Message-----
From: radsafe-bounces at health.phys.iit.edu [mailto:radsafe-bounces at health.phys.iit.edu] On Behalf Of KARAM, PHILIP
Sent: Wednesday, October 21, 2015 7:54 AM
To: The International Radiation Protection (Health Physics) Mailing List
Subject: Re: [ RadSafe ] DNA Repair

One thing I find interesting is that the rate of DNA mis-repair is remarkably consistent among widely disparate organisms - very low, but within an order of magnitude for microbes, mammals, and pretty much everything in between. To me, this suggests that there is an optimum error rate that typically conserves genetic information, but that "allows" a degree of experimentation; without this mis-repair, the highest form of life on Earth would likely still be the cyanobacteria. We need DNA repair, of course, to maintain genetic fidelity from one generation to the next - but perfect fidelity would make evolution, if not impossible, then at the least, very very slow.

Like others, I agree there is no need to invoke creationism - no matter how it is phrased. Basic scientific principles and laws seem quite adequate.

As an aside, Schroedinger wrote an extended essay called "What is Life" (adapted from a series of lectures he gave in the 1940s) in which he discusses - among other things - the inevitability of DNA mutations. This was the first work that really laid out the need for a "heredity molecule" as well as discussing how quantum mechanics made mutations (and, hence, evolution) inescapable. Watson and Crick both cited this work as inspiring their own research into the structure of DNA.


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